Opioids are narcotic analgesics. Immediate-release opioids, which are fast acting, have been evaluated for its usefulness in relieving dyspnea in patients with cancer and other palliative care patients with dyspnea symptoms. Fentanyl, a type of opioid, is considered separately in the categorization of relevant evidence for dyspnea treatment. Healthcare professionals should be aware of the different formulations for these medications, the length of their half-life, and the onset of action.